Mains powered with a long life lithium back-up battery, the FireAngel Pro series of alarms are available in two versions: with optical smoke or heat sensor. Up to 30 FireAngel Pro alarms can be hard wire interlinked within a single system, enabling all alarms to sound if any one of them detects a fire. The sealed 10 year lithium back-up battery is designed to last the life of the alarm and continues to provide power in the event of a mains failure.

In a wireless-only system the maximum number of compatible units that can interlink is 50, while a hard-wired-only system is limited to 30 units. In a mixed hard-wired and wireless alarm system these maximum quantities can be exceeded.

For each "group" of hard-wired alarms in a system, only one should be a wireless model. For example, in a 3 storey house you could hard-wire 2x ST-230 and 1x WST-230 alarms together on each floor with all of the WST-230 models wirelessly interlinked to each other. This can technically be done to a maximum of 50 groups of 30 alarms, though FireAngel has not designed, optimised, or tested these alarms for such a large system. Having so many alarms interlinked would create large communication delays between the alarms, potentially resulting in occupants not being given adequate warning of a fire. It is heavily recommended that customers desiring a large amount of alarms for a single property instead look into full Fire Alarm Systems which are designed for larger premises.

The table below shows all the units that can interlink with the FireAngel Pro alarms.